This dissertation explores the essence and resilience of the most sacred and secret ritual music of the Japanese imperial court---kagura taikyoku and kagura hikyoku---by examining ways in which these two songs have survived since their formation in the twelfth century. Kagura taikyoku and kagura hikyoku together are the jewel of Shinto ceremonial vocal music of gagaku, the imperial court music and dances. Kagura secret songs are the emperor's foremost prayer offering to the imperial ancestral deity, Amaterasu, and other Shinto deities for the well-being of the people and Japan. I aim to provide an understanding of reasons for the continued and uninterrupted performance of kagura secret songs, despite two major crises within Japan's history. While foreign origin style of gagaku was interrupted during the Warring States period (1467-1615), the performance and transmission of kagura secret songs were protected and sustained. In the face of the second crisis during the Meiji period (1868-1912), which was marked by a threat of foreign invasion and the re-organization of governance, most secret repertoire of gagaku lost their secrecy or were threatened by changes to their traditional system of transmissions, but kagura secret songs survived and were sustained without losing their secrecy, sacredness, and silent performance. This research addresses why and how kagura taikyoku and kagura hikyoku have persisted in the face of political and societal upheavals, and builds upon the pioneering work of Carl Folke and Jeff Todd Titon on resilience theory in the socio-ecological systems and ethnomusicology, respectively. Historical narrative is foundational to the thesis, which I have developed from examination of archived manuscripts that include the musical notations of kagura secret songs, housed in the National Archives and the Imperial Household Archives, as well as the musical manuscripts formerly owned by the Ayanok oji family, housed at the Tenri University Library in Japan. My analysis has been informed by the ethnographic method, while in residence and in interactions with the priests at Ise Jingu during periods of my field research between 2008 and 2016. Whereas contemporary priests' voices are not heard other than in the "Prelude, " their voices echo the ideas and sentiments of historical figures whose work I have examined. Hence, this dissertation can be viewed as a documentary history with ethnographic components that combine in offering an understanding of the continuity of Shinto ritual music and the unique religious affect that is associated with Shinto practices at Ise Jing? and in the imperial household. In sum, this research contributes to historical ethnomusicology, Japanese religious studies, and the advancement of gagaku.